Blast-resistant cargo container

ABSTRACT

A blast-resistant cargo container includes side panels and connecting members. The connecting members are mounted between the adjacent side panels to create a non-framed structure of the cargo container. Under ordinary conditions, the structure still has sufficient stiffness for loading goods. When an explosive blast occurs in the cargo container, the structure is flexible and utilizes membrane strength in the entire container structure, whereby the cargo container is capable of withstanding the explosive blast. Extruded bars can also be mounted around a bottom surface of the cargo container grooves are defined in the extruded bars and L-shaped flanges are formed on edges of the vertical side panels. Therefore, by receiving the L-shaped flanges into the grooves, the extruded bars are securely connected with the side panels.

BACKGROUND OF THE INVENTIONS

[0001] 1. Field of the Invention

[0002] The present invention relates generally to cargo containers, and more particularly concerns a blast-resistant cargo container that is capable of substantially confining an explosive blast within the cargo container for protecting a carrier such as an airplane.

[0003] 2. Description of Related Art

[0004] Conventional cargo containers are typically designed to have a frame, and panels attached to the frame so as to define a hollow interior for receiving goods. There are many kinds of available cargo containers having different sizes and configurations in order to meet practical needs, wherein an air cargo container is a kind to be used for transporting goods via an airplane.

[0005] Recently, airplanes have become a primary target for terrorist attacks, and many people have lost their lives in plane crashes due to terroist bombing. Therefore, the Federal Aviation Administration (FAA) and major airline companies all over the world are forced to enhance security checks before the custom in order to prevent explosives being smuggled on board. However, small plastic explosives are difficult to be detected despite current technology and are very likely to pass through the security checks. In the tragedies of Pan Am 103 1998 and UTA Flight 772 1989, the explosives were smuggled on board the jets and caused plane crashes that resulted in loss of hundreds of lives and properties. Therefore, to prevent these kinds of tragedies from happening, a lot of efforts have been made in the field of blast-resistant containers.

[0006] According to analysis and experiment research, an explosive blast destroys the cargo container in two stages. In the first stage, shock waves are generated and impact the cargo container in a short duration. In the second stage, sustained excessive pressure then destroys the cargo container. These two stages must be countered so as to make a container blast-resistant. During the moment and at the center of the explosive blast, the pressure from the blast can be hundred thousands times of atmospheric pressure. With the rapidly decay of the shock waves, the ensuing pressure exerted on the panels is still no less than tens times of the atmospheric pressure. With reflection and diffraction of the waves, the pressure becomes steady and the strength is much less than the shock waves. However, the pressure is still tens of times greater than the payload of the conventional cargo container. Therefore, the conventional cargo container is vulnerable to the explosive blast.

[0007] In order to overcome the mentioned problems, blast resistant techniques are applied to the cargo container, wherein the techniques can be divided into two main categories:

[0008] The first category utilizes the venting method, such as found in U.S. Pat. No. 5,195,701, wherein an air cargo container is provided with a deliberate weak point so that during the explosive blast, high pressure air breaks through the weak point and is thus vented in a controlled manner outside the air cargo container to prevent a total destruction. The key point in this method is that the weak point must be sufficiently large to effectively vent the air. Nevertheless, the high pressure air penetrating a large weak point can ultimately puncture the fuselage wall of the airplane. Although puncturing a wall may not usually be serious enough to cause a crash, damage to the airplane is still very costly to repair, and the time that the airplane is grounded is very expensive in lost income. Moreover, in some extreme cases, it is still possible for the high pressure air to damage the structure of the airplane and this results in a crash. Therefore, it is considered to be impractical to use the venting method to deal with the explosive blasts.

[0009] The second category utilizes the rigid confining method. With reference to FIG. 13, an air cargo container (40) designed according to this method is shown and has a rigid frame (41). Panels (42) made of energy-absorbing material are mounted onto the frame (41). The panels (42) must be inordinately thick enough so as that the wall can absorb destroying energy and to withstand the pressure of the explosive blast, and to further confine the pressure inside the air cargo container (40). However, in practice, what really destroys the structure of the air cargo container (40) is high stress, and high energy is not the most important factor. Besides, increasing the thickness of the panels (42) not only increases the cost, but also increases bending stress when encountering a blast inside the container. As a result, the increasing in the weight of the container is not acceptable by the aviation industry because the weight increase of the container means a lot more expenses will thus be incurred. Therefore, in order to overcome the high stress, the air cargo container (40) has to be constructed so heavily that it is not feasible to be carried by the airplane. Other related references can be found in the U.S. Pat. No. 6,237,793; U.S. Pat. No. 6,196,107 and U.S. Pat. No. 5,769,257. We found even though the container panel is made of high strength material, if the structure is not adapted, the panel and its edges nearby can be damaged by the explosive blast.

[0010] Therefore, the present invention intends to provide a blast-resistant cargo container to mitigate and/or obviate the aforementioned problems.

SUMMARY OF THE INVENTION

[0011] An objective of the present invention is to provide a blast-resistant cargo container that has a non-framed structure. Under ordinary conditions, the structure has sufficient stiffness for receiving goods. When an explosive blast occurs in the cargo container, the structure is flexible and by utilizing membrane stress in the entire structure, whereby the cargo container is capable of withstanding the explosive blast. The main purpose of this invention is to utilize the ductile connecting member to minimize the bending stress of the connecting members and the area of side panel edges.

[0012] In order to accomplish the objectives, a blast-resistant cargo container in accordance with the present invention includes side panels and connecting members. The connecting members are securely mounted between the adjacent side panels to form a flexible structure of the cargo container, whereby the flexible structure is able to substantially confine an explosive blast in the cargo container.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of the first preferred embodiment of a blast-resistant cargo container in accordance with the present invention;

[0014]FIG. 1A is a perspective view of the first preferred embodiment of a blast-resistant cargo container with the caps removed;

[0015] FIGS. 2-7 are cross-sectional views showing different embodiments of connecting members of the blast-resistant cargo container;

[0016]FIG. 8A-8C are schematic views showing different spacers are applied between th connecting members for reinforcement;

[0017]FIG. 9 is a perspective view of the second preferred embodiment of the blast-resistant cargo container;

[0018]FIG. 10 is a schematic, cross-sectional view showing a kind of connection between a side panel and an extruded bar, and deformation after an explosive blast is also shown;

[0019]FIG. 11 is a schematic, cross-sectional view showing another kind of connection between the side panel and the extruded bar, and the deformation after the explosive blast is also shown;

[0020]FIG. 12 is a schematic, perspective view showing the deformation of the blast-resistant cargo container after the explosive blast; and

[0021]FIG. 13 is perspective view of a conventional air cargo container with partial in section so as to show the structure thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] With reference to FIG. 1, the first preferred embodiment of a blast-resistant cargo container in accordance with the present invention is shown. The cargo container (10) has side panels (11) and connecting members (12) securely connecting adjacent side panels (11).

[0023] Referring to FIG. 2, each side panel (11) has arcuate shape in cross-section, and the connecting member (12) is composed of a first and a second connecting members (121,122) respectively attached to outer and inner surfaces of the adjacent side panels (11). It is to be noted from the drawing that after the first and the second connecting members (121,122) are attached to two adjacent side panels (11), there is no connection between two adjacent panels (11) and between two adjacent ends of two connecting members (12).

[0024] Referring to FIG. 3, both or either one of the first or the second connecting members (121,122) can be adjusted to have a substantial “S-shaped” cross-section. Referring to FIG. 4, one of the adjacent connecting members (12) can also be varied to have a crinkled cross-section. Referring to FIG. 5, either one of the first or the second connecting members (121,122) can be further varied to have a curve cross-section constituted by line segments. Referring to FIG. 6, the connecting members can be varied to have a “bubble-shaped” cross section. The objective of the variations in the connecting members (12,121,122) is to increase the stretching flexibility and enhance the overall structural strength when blasting in the container. Moreover, referring to FIG. 7, the adjacent side panels (11) can be connected by a single-pieced connecting member (12) instead of two as previously described. Referring to FIGS. 8A, 8B and 8C, it is noted that spacers (20) may be applied and securely engaged between the first and second connecting members (121,122) with continuous spacers or each one of the spacers (20) spatially parted from the other so as to reinforce the bending stiffness of the connecting members (12).

[0025] Referring to FIG. 1A, the main characteristic of the present invention is that the cargo container (10) applies a non-rigid frame design. That is, at corners where the connecting members (12) intersect, the connecting members (12) are not securely connected and caps (13) are respectively optionally disposed onto the corners. Each cap (13) is only connected to one of the side panels (11). That is, during the construction process of the air cargo of the present invention, when the cap (13) is applied, although the cap (13) is surrounded by three connecting members (12) and three side panels (11), the cap (13) is only securely connected to one of the adjacent three side panels (11). Under such an arrangement, the entire structure of the air cargo of the present invention is not rigid in corners and the stress concentration can be avoided or released. In the optionally disposed caps (13) case, the cap (13) is to be applied so that during an explosive blast the connecting members (12) and the side panels (11) are released in a controlled manner.

[0026] With reference to FIGS. 9 and 10, the second preferred embodiment of the blast-resistant cargo container in accordance with the present invention is shown. The cargo container (30) in this preferred embodiment also includes side panels (31) and connecting members (32) each securely connecting adjacent side panels (11). Extruded bars (34) are mounted around a bottom panel (35) of the cargo container (30) and securely connected with the bottom panel (35) by an extension (342) of the extruded bar (34).

[0027] With reference to FIG. 10 again, each of the extruded bars (34) has a groove (341) defined therein. Each of the side panels (31) has a bottom portion securely connected with a connecting panel (311). Each connecting panel (311) further has a bottom edge formed as a L-shaped flange (312) so that by receiving the L-shaped flange (312) in the corresponding groove (341), the side panels (31) are respectively connected to the extruded bars (34). It should be appreciated that when the explosive blast occurs in the cargo container (30), the side panels (31) are displaced outwardly but not detached from the extruded bars (34) due to the mating between the L-shaped flanges (312) and the grooves (341).

[0028] With reference to FIG. 11, each side panel (31) can also have its bottom edge formed as a L-shaped flange (310) so as to be received in the groove (341). Therefore, in the explosive blast, as the side panels (31) are directly connected to the extruded bars (34) the side panels (31) are displaced outwardly but not detached from the extruded bars (34) due to the mating between the flanges (310) and the grooves (341).

[0029] It should be appreciated that the connecting members (12 and 32) in the described embodiments are preferably made of high ductile material, such as stainless steel or aluminum. Furthermore, the side panels (11 and 31) and the bottom panel (35) are preferably made of material with high tensile strength.

[0030] The cargo container (10 or 30) in accordance with the present invention is designed to have sufficient stiffness for loading goods. When the explosive blast occurs in an interior of the cargo container (10 or 30), due to the unique design, a flexible structure is formed and expands to fully utilize membrane stress of the side panels (11 or 31). Thereby, the explosive blast is substantially confined in the cargo container (10 or 30) as shown in FIG. 12.

[0031] In addition, when the blast waves generated in the explosive blast those high density blast “particles” will impact the side panels (11 or 31), the side panels (11 or 31) displace outwardly so that the blast “particles” temporarily separate from the side panels (11 or 31) and impact again afterwards. This process can be considered as a series of nonelastic collisions and the explosive blast energy is absorbed in increments of entropy to reduce confined pressure exerted on the structure of the cargo container (10 or 30). In summary, the structure not only utilizes the membrane stress to withstand the explosive blast, but also appropriately expands to reduce the confined pressure.

[0032] From the above description, it is noted that the invention has the following advantages:

[0033] 1. The cargo container is constructed by connecting of side panels and the absence of a conventional frame enables the more flexible structure to be formed. In the explosive blast, the side panels can bear force uniformly to utilize the membrane stress and prevent bending stress near its edges. Therefore, the cargo container can be light in weight while still being capable of confining the explosive blast therein.

[0034] 2. The mating between the flanges and the grooves in the bottom surface is not only convenient to assemble, but also is more flexible to allow large deformation so as to withstand the explosive blast.

[0035] 3. The connecting members can be easily adapted to connect side panels having different thickness. Therefore, the assembly of the cargo container is convenient.

[0036] While this invention has been particularly shown and described with references to the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. 

What is claimed is:
 1. A blast-resistant cargo container comprising: multiple side panels; and multiple connecting members, wherein the connecting members are securely mounted between adjacent side panels to form a flexible structure of the cargo container, whereby the flexible structure is able to confine an explosive blast in the cargo container.
 2. The blast-resistant cargo container as claimed in claim 1 further comprising multiple bars securely mounted around a bottom panel of the cargo container, wherein each of the bars has an groove defined therein, and the side panels to be connected to the bars each has an L-shaped flange formed at an edge thereof, the L-shaped flange is received in the corresponding groove so as to securely connect the side panels and the bars.
 3. The blast-resistant cargo container as claimed in claim 1, wherein the connecting members are made of a ductile material.
 4. The blast-resistant cargo container as claimed in claim 1, wherein every adjacent connecting panel has at least one of the connecting members securely mounted therebetween.
 5. The blast-resistant cargo container as claimed in claim 1, wherein every adjacent connecting panel has two layers of the connecting members securely mounted therebetween, the two layers are respectively connected with inner surfaces and outer surfaces of the adjacent connecting panels.
 6. The blast-resistant cargo container as claimed in claim 1, wherein each of the connecting members has an arcuate cross-section.
 7. The blast-resistant cargo container as claimed in claim 5, wherein at least one layer of the connecting members has a curve cross-section constituted by line segments.
 8. The blast-resistant cargo container as claimed in claim 5, wherein at least one layer of the connecting members has a bubble-shaped cross-section.
 9. The blast-resistant cargo container as claimed in claim 5, wherein at least one layer of the connecting members has a crinkled cross-section.
 10. The blast-resistant cargo container as claimed in claim 5, wherein at least one spacer is disposed between the two layers of the connecting members for reinforcement.
 11. The blast-resistant cargo container as claimed in claim 1, wherein a cap is mounted at each corner where the connecting members intersect.
 12. The blast-resistant cargo container as claimed in claim 1 further comprising multiple bars securely mounted around a bottom panel of the cargo container, wherein each of the bars has a groove defined therein, each of the side panels was securely connected with an L-shaped connecting member in its bottom portion, each connecting member further has a bottom edge formed as a flange to be received in the corresponding groove so as to securely connect the side panels and the bars.
 13. The blast-resistant cargo container as claimed in claim 11, wherein the cap is only connected to one of the side panels.
 14. The blast-resistant cargo container as claimed in claim 2, wherein the multiple bars are extruded bars.
 15. The blast-resistant cargo container as claimed in claim 12, wherein the multiple bars are extruded bars.
 16. The connecting members as claimed in claim 3, wherein the material can be selected from the metal consisting of stainless and aluminum.
 17. The blast-resistant cargo container as claimed in claim 1, wherein the side panels are made of high tensile strength material.
 18. The blast-resistant cargo container as claimed in claim 17, wherein the metal includes laminated composite, fiber-reinforced metal laminates and high strength aluminum.
 19. The blast-resistant cargo container as claimed in claim 12, wherein the connecting members are made of ductile metal.
 20. The blast-resistant cargo container as claimed in claim 12, wherein the connecting members are extruded members. 